System and apparatus for switch and foot pedal tap detection and filtering

ABSTRACT

An ocular surgical apparatus is provided, including a surgical control device such as a foot pedal configured to be employed to control at least one ocular surgical parameter, and a controller configured to receive a series of values from the surgical control device and evaluate the series of values provided from the surgical control device, the series of values provided using a buffer comprising a detection area and an exclusion area. Presence of a desired value in the detection area and an absence of a contrary indication in the exclusion area is determined by the controller to indicate a switch associated with the surgical control device is requested by a user of the surgical control device.

CROSS REFERENCE TO RELATED APPLICATION

This application claim priority to U.S. Provisional Application No.61/983,324, filed on Apr. 23, 2014, entitled “System and Apparatus forSwitch and Foot Pedal Tap Detection and Filtering,” the entirety ofwhich is incorporated by reference as if set forth herein.

BACKGROUND

1. Field of the Invention

The present invention relates generally to the field of surgicalprocedures, and more specifically to the enhanced control of medicaldevices such as foot pedals and switches used in surgical procedures.

2. Description of the Related Art

Ocular surgical procedures include phacoemulsification, diathermy, andvitrectomy procedures.

Phacoemulsification refers to a method of lens and cataract extractionfrom an eye. The procedure includes an ultrasonically vibrated needlewhich is inserted through a very small incision in the cornea in orderto provide energy for emulsifying or breaking up of the lens andcataract which then can be aspirated and removed through the incision.

Diathermy refers to a method of cautery to seal severed or rupturedblood vessels. Diathermy is used in ophthalmic surgery to halt bleedingassociated with surgical incisions

Vitrectomy surgery has been successfully employed during cataractsurgery when the posterior capsular bag has been broken and in thetreatment of retinal detachments resulting from tears or holes in theretina. In cataract surgery, the same incision used for thephacoemulsification handpiece is used for inserting the vitrector toremove the vitreous gel. Vitrectomy surgery typically involves removalof vitreous gel and may utilize three small incisions in the pars planaof the patient's eye. These incisions allow the surgeon to pass threeseparate instruments into the patient's eye to affect the ocularprocedure. The surgical instruments typically include a vitreous cuttingdevice, an illumination source, and an infusion port.

Phacoemulsification and vitrectomy procedures may require fluid control,namely control over aspiration and irrigation to the ocular region, andemploy a handpiece that is typically electrically driven and must becontrolled. As the surgeon is employing the handpiece and possibly afluid handpiece during surgery, control is provided to the surgeon via afoot pedal. Foot pedals vary in design, but more modern foot pedalsinclude a treadle that can be moved in a fore-and-aft direction (a pitchmotion) and in a left-and-right direction (a yaw motion). Hard switchesare also provided, where the switches typically provide a togglefunctionality and/or an on-off functionality. Control can be providedfor various device components and operations for thephacoemulsification, diathermy or vitrectomy machine, including controlof fluid flow, entry into various modes, electrical parameters, speedparameters (e.g. cut speed), and so forth.

One of the issues with traditional foot pedals is the dexterity requiredto perform multiple foot pedal operations, i.e. engage the foot pedal atmultiple positions or to perform more than one function. For example, asurgeon may be controlling fluid flow using movement of the treadle inthe pitch and yaw axes, attaining a certain position to achieve desiredfluid flow balance, and may then need to engage a switch to raise orlower the height of an irrigation source, such as an irrigation bottle.It can be difficult to maintain the desired level of fluid flow, i.e.maintain the desired treadle position, and at the same time engage afootswitch without either disrupting fluid flow or altering fluid flowand subsequently attempting to reacquire the same fluid flow state inthis example. Foot pedal switches have been offered at differentpositions on different foot pedals, but generally are located proximatethe treadle, such as at the sides, near the base, or at the forward tipof the treadle. In certain foot pedal designs, top switches are providedthat are on the underside of the top of an enclosed foot pedal.

Such foot pedal switches may be electromechanical, and such switchestend to increase the cost and complexity of foot pedal design, and havean increased chance of failure. As with any device having multiplecomponents, failure of one component can result in the device beingunusable in its entirety, and loss of a foot pedal or any of itsfunctions can be highly problematic.

Further, existing foot pedal switches can be sensitive and at timesinaccurate as far as detection of engagement. Certain transient orinadvertent physical actions may be considered switch engagements whenin actuality they are nothing more than spurious events. Suchsensitivities are undesirable and should be minimized.

Based on the foregoing, it would be advantageous to provide a foot pedaldesign that limits the need for foot pedal switch functionality, and/orprovides an ability to distinguish engagement of a foot pedal switchfrom an inadvertent transient or momentary occurrence. Such a designwould afford a surgeon the ability to engage desiredphacoemulsification, diathermy, or vitrectomy functions with less needto employ foot pedal switches, and/or obtain better performance fromfoot pedal switches.

SUMMARY

Thus according to one aspect of the present invention, there is providedan ocular surgical apparatus comprising a surgical control device, suchas a foot pedal, configured to be employed to control at least oneocular surgical parameter, and a controller configured to receive aseries of values from the surgical control device and evaluate theseries of values provided from the surgical control device, the seriesof values provided using a buffer comprising a detection area and anexclusion area. Presence of a desired value in the detection area and anabsence of a contrary indication in the exclusion area is determined bythe controller to indicate a switch associated with the surgical controldevice is requested by a user of the surgical control device.

According to another embodiment of the present design, there is provideda method for use in an ocular surgical device, comprising operating asurgical control device (e.g. foot pedal) to control at least one ocularsurgical parameter, receiving a series of values from the surgicalcontrol device using a buffer comprising a detection area and anexclusion area, and controlling a parameter of the ocular surgicaldevice based on contents of the buffer. Presence of a desired value inthe detection area and an absence of a contrary indication in theexclusion area indicate a switch associated with the surgical controldevice is requested by a user of the surgical control device.

According to another embodiment of the present design, there is provideda surgical control device (e.g. foot pedal) configured to be employed tocontrol at least one ocular surgical parameter and a controllerconfigured to receive a series of values from the surgical controldevice, evaluate the series of values provided from the surgical controldevice, the series of values provided using a buffer comprising adetection area and an exclusion area, and control an attribute of theocular surgical apparatus when the series of values indicates a userdesires a switch of the attribute based on user input received from thesurgical control device. Presence of a desired value in the detectionarea and an absence of a contrary indication in the exclusion area isdetermined by the controller to indicate a switch associated with thesurgical control device is requested by the user of the surgical controldevice.

Other features and advantages of the present invention should beapparent from the following description of exemplary embodiments, whichillustrate, by way of example, aspects of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrates an exemplaryphacoemulsification/diathermy/vitrectomy system in accordance with thepresent design;

FIG. 2A illustrates an example of a foot pedal that may be employed withthe current design;

FIG. 2B is an alternate view of a foot pedal that may be employed withthe current design;

FIG. 3 illustrates a region of travel in the pitch direction for thetreadle of a foot pedal;

FIG. 4 shows the full range of travel in the yaw or side-to-sidedirection for the treadle of a foot pedal;

FIG. 5 illustrates the running first in, first out (FIFO) bufferelements in an example 10 element buffer;

FIG. 6 is an example of switch click filtering, nonsequential in timeand showing discrete “snapshots” in time;

FIG. 7 illustrates an example of foot pedal tap filtering such as whenthe foot pedal treadle enters a desired zone in order to effectuate aswitch function, again nonsequential in time and illustrating discrete“snapshots” in time;

FIG. 8 is a sequential example of switch click filtering;

FIG. 9 shows a sequential example of foot pedal tap filtering, such aswhen the foot pedal treadle enters a desired zone in order to effectuatea switch function; and

FIG. 10 is a flowchart example of operation of the present design.

DETAILED DESCRIPTION

The following description and the drawings illustrate specificembodiments sufficiently to enable those skilled in the art to practicethe system and method described. Other embodiments may incorporatestructural, logical, process and other changes. Examples merely typifypossible variations. Individual components and functions are generallyoptional unless explicitly required, and the sequence of operations mayvary. Portions and features of some embodiments may be included in orsubstituted for those of others.

The present design provides a system and method for foot pedal controlthat detects foot pedal treadle zone or switch readings as conforming todesired foot pedal switch engagement, using at least one running bufferincluding fields specific to each switch or foot pedal treadle zone, anddeciding under certain conditions whether a click or tap of a switch hasbeen detected.

The present design will be discussed herein with a particular emphasison a medical or hospital environment where a surgeon or health carepractitioner performs. For example, an embodiment of the present designis a phacoemulsification surgical system that comprises an integratedhigh-speed control module for the vitrectomy handpiece. The surgeon mayadjust or set the cutting speed via a graphical user interface (GUI)module or a foot pedal to control the high-speed pneumatic vitrectomyhandpiece.

FIG. 1 illustrates an exemplary phacoemulsification/diathermy/vitrectomysystem 100 in a functional block diagram to show the components andinterfaces for a safety critical medical instrument system that may beemployed in accordance with the present design. GUI host 101 andinstrument host 102 reside on a single-board computer and communicatethrough inter-process communication. A processor (not shown) may beprovided to control instrument host 102 and GUI host 101. Instrumenthost 102 typically takes the form of a computational device in thearrangement shown, but other arrangements are possible. An interfacecommunications cable (not shown) may be connected to instrument host 102for distribution of instrument sensor data, and may distributeinstrument settings and parameter information to other systems,subsystems and modules within and external to the instrument host 102.An interface communications cable may be connected or realized on anyother subsystem (not shown) that could accommodate such an interfacedevice able to distribute required data.

Foot pedal 104 may also be provided as part ofphacoemulsification/diathermy/vitrectomy system 100. A switch moduleassociated with foot pedal 104 may transmit control signals relatingfoot pedal physical and virtual switch position information as input tothe instrument host 102 over serial communications cable 105. A wirelessfoot pedal may alternately be provided. Instrument host 102 may includea database file system for storing configuration parameter values,programs, and other data saved in a storage device (not shown).

Also shown in FIG. 1 is a phacoemulsification handpiece 110 thatincludes a needle and electrical means, typically a piezoelectriccrystal, for ultrasonically vibrating the needle. The instrument host102 supplies power on line 111 to a phacoemulsification handpiece 110.An irrigation fluid source 112 can be fluidly coupled to handpiece 110through line 113. The irrigation fluid and ultrasonic power are appliedby handpiece 110 to an eye, or affected area or region, indicateddiagrammatically by block 103. Alternatively, the irrigation source maybe routed to eye 103 through a separate pathway independent of thehandpiece. Aspiration is provided to eye 103 by a pump (not shown), suchas a peristaltic pump and/or Venturi pump, via the instrument host 102,through lines 115 and 116. A surgeon/operator may select an amplitude ofelectrical pulses using the handpiece, or via the instrument host 102and GUI host 101, or using foot pedal 104.

One example of a foot pedal such as foot pedal 104 for use in such asystem is presented in FIG. 2A. FIG. 2A shows treadle 201 and switches202 and 203. A further switch 204 is shown in this view. FIG. 2Billustrates switches 202, 203, and 204, and further switch 205. Thedepiction in FIGS. 2A and 2B are one example of a foot pedal, but otherfoot pedals may be used with this design. Other foot pedals can havedifferent switch and treadle configurations, such as heel, toe, and topswitches.

As noted, one aspect of the present design seeks to minimize the need toemploy the switches on the foot pedal by providing a unique controlmechanism. The control mechanism takes treadle orientation and dividesangular regions of travel of the treadle into zones. When a surgeon isin a zone and taps the treadle, depending upon the nature of the tap,i.e. time duration, the tap may be considered to have engaged aparticular switch without the need to orient his foot elsewhere on thefoot pedal or “stomp” or otherwise engage a particular hardwareelectromechanical switch with his foot.

FIG. 3 illustrates a region of travel in the pitch direction for thetreadle of a foot pedal. At an unengaged state, the treadle willtypically be in the dead band zone 301. Zones FP0, FP1, FP2, and FP3 areprovided, as well as a further dead band zone 302. In operation, onemovement to engage a switch may be for the surgeon to move the treadleinto region FP1 and a return to FP0 to indicate a desired switch usingpitch mode. This is an example, and other implementations are possible.

Zero switch 303 is a location within the dead band zone 301 thatindicates that a user has fully released the treadle of the foot pedal.The zero switch 303 may be located anywhere within the dead band zone,and in one embodiment the zero switch 303 may be at, near, or past thecenter point of the dead band 301 and closer to the FP0 zone.

FIG. 4 shows the full range of travel in the yaw or side-to-sidedirection, Two outer position 401. Such movement indicates a desiredswitch, i.e. in the yaw mode this movement is the “tap” that indicates aswitch using yaw mode. Dead band zones 402 and 403 are shown in thisview. Again, this is an example, and other operations are possible.

The present design employs a running buffer that may be of any size, butfor purposes of this particular example, ten buffer elements arepresented. FIG. 5 illustrates the running buffer elements in a 10element buffer, where new readings are added on the left side and thelast or oldest reading is removed, and all buffer elements progresssequentially from left to right. As an example, all buffer elements mayinclude zero, and when a switch is selected or a foot pedal treadleenters a zone, a value such as one is provided in the leftmost elementin this view. In the next frame, which may be X milliseconds later, the1 value moves to the second element from the left and progresses fromleft to right.

FIG. 5 shows a primary detection slot 501, indicating a primary slotevaluated to determine the status of the variable, be it a switchselection, change of mode, tap of a foot pedal treadle in a zone, entryof the treadle into a zone, or otherwise. Slot 502 is a secondarylimitation, generally indicating that the value entered in this regioncould be anything—a zero, one, or other number, and depending uponwhether the running buffer is detecting for a valid switch click, footpedal tap, and so forth, determine whether the value entry has an effecton the status of the primary detection region 501. Finally, two areas503 and 504 are shown, where these areas regions indicate tertiaryexclusions, indicating any value other than zero provided in theseareas, i.e. in any field in the area, is a contrary or exclusionaryindication. Such a contrary or exclusionary indication means that evenif the region or slot 501 includes a value of “1,” a value of “1” in anyof these regions negates the status of the switch, tap, mode, orfunction. For example, if region 501 includes a “1,” indicating a switchselection, and area 503 includes a “1” in the second region from theleft, the “1” in region 501 is negated by the “1” in area 503 such thatno switch selection has occurred.

As may be appreciated, different regions may be primary detection areas,secondary limitation areas, and tertiary exclusion areas, and such areasmay be contiguous or discontinuous. Further, logic may be employed tovary functionality, such as if a primary detection is indicated and atertiary exclusion is also indicated, the secondary limitation acts as a“tie-breaker,” such that a value of “1” in the secondary regionindicates selection of the switch, tap, mode, or function associatedwith the primary detection area. Further region hierarchies may beprovided.

FIG. 6 presents a switch click filtering embodiment, wherein the systemseeks to determine whether a signal indicating a switch has beenactivated is a valid switch click, i.e. a switch was meant to beactivated, based on multiple readings over a period of time. The runningbuffer examples in FIG. 6 and FIG. 7 represent discrete snapshots intime and from top to bottom are not meant to represent a sequential setof buffer states. These are “snapshots” in time representing individualand discrete states of a running buffer that indicate valid and invalidstates for the validation of the receipt of a switch selection, e.g. abutton click or tap. FIG. 6 follows the primary detection, secondarylimitation, and tertiary exclusion requirements of FIG. 5 and operatesas discussed with respect to FIG. 5, i.e. new readings come in from theleft and the rightmost reading is dropped every frame, and primarydetection is indicated in the fifth region from the left in this view.

From FIG. 6, buffer 601 is filled with zeros, indicating no switchselection has occurred—the value in the primary detection area is zero.In buffer 602, not only is there a “0” in the primary detection region,there is a contrary “1” in a tertiary exclusion region, and thus novalid click has occurred or been detected, and as a result the functionassociated with the switch is not effectuated. Buffer 603 shows a “1” inthe secondary limitation area, but in this scenario, this region has nobearing on the switch selection and again no valid “click” has occurred.In buffer 604, a “1” is provided in the primary detection region, nocontrary indications are presented, and thus the switch is consideredselected as a valid “click” and the function associated with the switchis effectuated. Buffer 605 also has a “1” in the primary detectionregion and a “1” in the secondary detection region, and thus the switchstatus is “valid.” Buffer 606 illustrates positive indications in boththe primary detection region and the secondary limitation region, but acontrary indication in a tertiary exclusion region. Thus the positivevalue in the tertiary exclusion area overrides the positive indicationin the primary detection area. As a result, no switch indication isprovided. Finally, in region 607, “1” values are provided in the primarydetection and secondary limitation area, but several contraryindications are provided, again resulting in a “no valid click”condition or state.

FIG. 7 similarly shows discrete and nonsequential buffer states and ismeant for instructional purposes. In general, FIG. 7 represents footpedal tap filtering, where the foot pedal is used to indicate sensing ofa change in function. For example, referring to FIG. 3, moving into FP1then returning to FP0 in the pitch direction may be considered a switchsuch that the tap of the foot pedal registers as activating a particularfunction of the system, and the buffer regions in FIG. 7 representparticular conditions, i.e. the treadle is in region FP0, in region FP1,in region FP2, in region FP3, in a dead zone, etc.

From FIG. 7, buffer 701 is filled with zeros and thus no valid tap isconsidered to have occurred. In buffer 702, not only is there a “0” inthe primary detection region, there is a contrary “1” in a tertiaryexclusion region, and thus no valid tap selection has occurred so thefunction associated with the switch/tap does not occur. Buffer 703 showsa “1” in the secondary limitation area, in this example this region hasa bearing on the switch selection to determine what foot pedal positionthe treadle is in as the switch or recognized tap is only activated inFP1 so the secondary limitation will be exclusionary for everythingexcept a “0” or a “1”, where the number corresponds to the foot pedalposition (e.g. FP0 equals “0”; FP1 equals 1; FP2 equals 2; FP3 equals 3,and so forth). Thus, for buffer 703 no valid tap selection has occurred.

In buffer 704, a “1” is provided in the primary detection region, nocontrary indications are presented, and thus the tap is consideredvalid. Buffer 705 also has a “1” in the primary detection region and a“1” in the secondary detection region, and thus the switch status is“valid.” Buffer 706 includes a value of “2” in the primary detectionarea, which is not an accepted tap condition of “1” and the result isthat no valid tap has occurred with the arrangement of buffer 706.Similarly, buffer 707 provides a value of “3” in the primary detectionarea, and again, since “3” is not “1,” the tap is not valid.

Buffer 708 illustrates another particular situation wherein the primarydetection area includes a “1,” but the secondary limitation includes a“2” rather than a “1” or zero. This may be an error condition, in thatthe only valid values for secondary limitation regions is to include a“1” or a zero, and the number “2” or any other number is invalid. Thuseven though the primary detection area is “1” and the secondarylimitation area is essential to the buffer and the fact that the valueis outside the acceptable values is an error and is considered to be anon-switch or invalid tap condition. Similarly, buffer 709 includes thevalue “3” in the secondary limitation area and is thus invalid, and novalid tap has occurred. Finally, buffer 710 includes “1” values in theprimary detection and secondary limitation areas, but several contraryindications are provided, again resulting in a “no valid tap” conditionor state.

In general, the functionality described herein and the assessment ofbuffer, area, and region contents can be performed by a controllerlocated with the foot pedal or with a remote device, such as aphacoemulsification/diathermy/vitrectomy device. In general, any type ofdevice that can make the determinations required, such as evaluating thebuffer contents presented in FIGS. 6 and 7, can be employed, and suchfunctionality may be provided in hardware or software and/or distributedwithin one or more than one computing or processing devices.

FIG. 8 illustrates a sequential example for a click or pitch based tap,but is applicable to switch clicks or other types of taps. The number“1” indicates an entry into region FP1, indicating a valid pitch tapmotion indicating a switch request. Eight buffers are presented, andbuffer 801 includes all zeros, and thus no pitch tap or switch has beendetected. Buffer 802 includes a “1” in the first position, a tertiaryexclusion region, and thus the pitch tap or switch detected was not avalid pitch tap or switch. The “1” value progresses sequentially inbuffers 803 to 805 within the tertiary exclusion area, and at buffer 806enters the secondary limitation area, but the primary detection arearemains zero, indicating no valid tap. Buffer 807 shows the “1” enteringthe primary detection region, meeting the criteria or requirement for avalid pitch tap condition being detected resulting in the functionassociated with the switch/pitch tap occurring or being activated. Thepattern for buffer 807 is a pattern that meets the criteria for a validpitch tap or selection of a switch. In this example, the existence of avalid pitch tap results in an activation of the feature associated withthe pitch zone and a reset condition such that all regions in the bufferare set to zero, shown in buffer 808.

FIG. 9 illustrates a sequential example for a yaw based tap, but is alsoapplicable to switch clicks or other types of taps. The number “3”indicates an entry into region YP3, indicating a valid yaw tap motionindicating a switch request. Eight buffers are presented, and buffer 901includes all zeros, and thus no click or switch has been detected.Buffer 902 includes a “3” in the first position, a tertiary exclusionregion, and thus the click or switch detected was not a valid click orswitch. The “3” value progresses sequentially in buffers 903 to 905within the tertiary exclusion area, and at buffer 906 enters thesecondary limitation area, but the primary detection area remains zero,indicating no valid yaw tap. Buffer 907 shows the “3” entering theprimary detection region, meeting the criteria or requirement for avalid yaw tap condition being detected resulting in the functionassociated with the switch/yaw tap occurring or being activated. Thepattern for buffer 907 is a pattern that meets the criteria for a validyaw tap or selection of a switch. In this example, the existence of avalid yaw tap sensed results in an activation of the feature associatedwith the yaw zone and a reset condition such that all regions in thebuffer are set to zero, shown in buffer 908.

The present design identifies clicks or taps as discrete events overtime and prevents false positive readings. Clicks are identified basedon proximity of positive readings over time and/or foot pedal treadleangular position for each reading.

Any type of device, such as a twist knob or lever, can be monitored todetermine when a switch has been activated in the manner disclosed.

An example flowchart representing operation is shown in FIG. 10. FromFIG. 10, point 1001 indicates the default state of the switch beingunselected—switch undetected. Point 1002 evaluates whether the desiredvalue is in the primary detection region. If not, the system cycles backto point 1001 indicating the switch is undetected. At point 1003, thesystem determines whether an undesired value is present in an exclusionarea, such as the tertiary exclusion area 503 or 504. If so, the systemcycles back to position 1001 and the switch is not selected. If not, thesystem may evaluate whether invalid data is present at point 1004. Ifinvalid data is present, such as invalid data in the secondarylimitation area 502 or primary detection area 501, the systemtransitions to point 1001 and again, no switching has occurred. If,however, no invalid data is present, the desired value is in the primarydetection region and no undesired value is in the exclusion area, thesystem indicates the switch is selected at point 1005, and the buffersmay be reset at point 1006. This represents an example, and otherconditions may be evaluated as desired, such as evaluating whether acertain amount of time has passed, determining whether conflictingindications are present, and so forth.

Thus the present design includes an ocular surgical apparatus comprisinga surgical control device, such as a foot pedal, configured to beemployed to control at least one ocular surgical parameter, and acontroller configured to receive a series of values from the surgicalcontrol device and evaluate the series of values provided from thesurgical control device, the series of values provided using a buffercomprising a detection area and an exclusion area. A limitation area mayalso be provided. Presence of a desired value in the detection area andan absence of a contrary indication in the exclusion area is determinedby the controller to indicate a switch associated with the surgicalcontrol device is requested by a user of the surgical control device.

Alternately, the present design includes a method for use in an ocularsurgical device, comprising operating a surgical control device (e.g.foot pedal) to control at least one ocular surgical parameter, receivinga series of values from the surgical control device using a buffercomprising a detection area and an exclusion area, and controlling aparameter of the ocular surgical device based on contents of the buffer.Presence of a desired value in the detection area and an absence of acontrary indication in the exclusion area indicates a switch associatedwith the surgical control device is requested by a user of the surgicalcontrol device.

One embodiment of the present design includes an ocular surgicalapparatus comprising a surgical control device (e.g. foot pedal)configured to be employed to control at least one ocular surgicalparameter and a controller configured to receive a series of values fromthe surgical control device, evaluate the series of values provided fromthe surgical control device, the series of values provided using abuffer comprising a detection area and an exclusion area, and control anattribute of the ocular surgical apparatus when the series of valuesindicates a user desires a switch of the attribute based on user inputreceived from the surgical control device. Presence of a desired valuein the detection area and an absence of a contrary indication in theexclusion area is determined by the controller to indicate a switchassociated with the surgical control device is requested by the user ofthe surgical control device.

Those of skill in the art will recognize that any step of a methoddescribed in connection with an embodiment may be interchanged withanother step without departing from the scope of the invention. Those ofskill in the art would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the embodiments disclosed herein may be implemented aselectronic hardware, computer software, or combinations of both. Toclearly illustrate this interchangeability of hardware and software,various illustrative components, blocks, modules, circuits, and stepshave been described above generally in terms of their functionality.Whether such functionality is implemented as hardware or softwaredepends upon the particular application and design constraints imposedon the overall system. Skilled artisans may implement the describedfunctionality in varying ways for each particular application, but suchimplementation decisions should not be interpreted as causing adeparture from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits describedin connection with the embodiments disclosed herein may be implementedor performed using a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with theembodiments disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in RAM memory, flash memory, ROM memory,DOM memory, EPROM memory, EEPROM memory, registers, hard disk, aremovable disk, a CD-ROM, or any other form of storage medium known inthe art. An exemplary storage medium is coupled to the processor suchthe processor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

The previous description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the presentinvention. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the invention. Thus, the present invention is notintended to be limited to the embodiments shown herein but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. An ocular surgical apparatus comprising: asurgical control device configured to be employed to control at leastone ocular surgical parameter; and a controller configured to receive aseries of values from the surgical control device and evaluate theseries of values provided from the surgical control device, the seriesof values provided using a buffer comprising a detection area and anexclusion area; wherein presence of a desired value in the detectionarea and an absence of a contrary indication in the exclusion area isdetermined by the controller to indicate a switch associated with thesurgical control device is requested by a user of the surgical controldevice.
 2. The ocular surgical apparatus of claim 1, wherein thesurgical control device comprises a foot pedal.
 3. The ocular surgicalapparatus of claim 1, wherein the buffer further comprises a secondarylimitation area and the presence of an unacceptable value in thesecondary limitation area indicates no switching is requested by theuser of the surgical control device.
 4. The ocular surgical apparatus ofclaim 1, wherein the buffer comprises samples taken at discrete pointsin time and contents of the buffer progress in a first in, first out(FIFO) manner.
 5. The ocular surgical apparatus of claim 1, wherein thecontroller determining the switch is requested causes the controller toprovide a switching request to a component in the ocular surgicalapparatus.
 6. The ocular surgical apparatus of claim 1, wherein presenceof invalid data in any buffer region indicates no switching is requestedby the user of the surgical control device.
 7. The ocular surgicaldevice of claim 1, wherein user initiation of a desired movement causesan indication to be provided to the buffer and after a predeterminedperiod of time the indication progresses to the detection area.
 8. Amethod for use in an ocular surgical device, comprising: operating asurgical control device to control at least one ocular surgicalparameter; receiving a series of values from the surgical control deviceusing a buffer comprising a detection area and an exclusion area; andcontrolling a parameter of the ocular surgical device based on contentsof the buffer; wherein presence of a desired value in the detection areaand an absence of a contrary indication in the exclusion area indicate aswitch associated with the surgical control device is requested by auser of the surgical control device.
 9. The method of claim 8, whereinthe surgical control device comprises a foot pedal.
 10. The method ofclaim 8, wherein the buffer further comprises a secondary limitationarea and the presence of an unacceptable value in the secondarylimitation area indicates no switching is requested by the user of thesurgical control device.
 11. The method of claim 8, wherein the buffercomprises samples taken at discrete points in time and contents of thebuffer progress in a first in, first out (FIFO) manner.
 12. The methodof claim 8, wherein presence of invalid data in any buffer regionindicates no switching is requested by the user of the surgical controldevice.
 13. The method of claim 8, wherein user initiation of a desiredmovement causes an indication to be provided to the buffer and after apredetermined period of time the indication progresses to the detectionarea.
 14. An ocular surgical apparatus comprising: a surgical controldevice configured to be employed to control at least one ocular surgicalparameter; and a controller configured to: receive a series of valuesfrom the surgical control device; evaluate the series of values providedfrom the surgical control device, the series of values provided using abuffer comprising a detection area and an exclusion area; and control anattribute of the ocular surgical apparatus when the series of valuesindicates a user desires a switch of the attribute based on user inputreceived from the surgical control device; wherein presence of a desiredvalue in the detection area and an absence of a contrary indication inthe exclusion area is determined by the controller to indicate a switchassociated with the surgical control device is requested by the user ofthe surgical control device.
 15. The ocular surgical apparatus of claim14, wherein the surgical control device comprises a foot pedal.
 16. Theocular surgical apparatus of claim 14, wherein the buffer furthercomprises a secondary limitation area and the presence of anunacceptable value in the secondary limitation area indicates noswitching is requested by the user of the surgical control device. 17.The ocular surgical apparatus of claim 14, wherein the buffer comprisessamples taken at discrete points in time and contents of the bufferprogress in a first in, first out (FIFO) manner.
 18. The ocular surgicalapparatus of claim 14, wherein presence of invalid data in any bufferregion indicates no switching is requested by the user of the surgicalcontrol device.
 19. The ocular surgical device of claim 14, wherein userinitiation of a desired movement causes an indication to be provided tothe buffer and after a predetermined period of time the indicationprogresses to the detection area.